Voltage converter and operation method thereof

Abstract

A voltage converter includes a first circuit including a first switch, a second switch, an inductor and a current source, the first circuit being configured to convert an input voltage into an output voltage based on a switching operation of the first switch and the second switch, and processing circuitry configured to generate a first reference voltage and a second reference voltage, control the switching operation of the first switch and the second switch based on an inductor current flowing in the inductor, the output voltage and the first reference voltage, reduce the first reference voltage and the second reference voltage to a reset voltage during a soft-stop time period of a soft-stop phase, and control a discharge current flowing in the current source in the soft-stop phase based on a magnitude of the inductor current, the output voltage and the second reference voltage.

What is claimed is: 
     
         1 . A voltage converter comprising:
 a first circuit including a first switch, a second switch, an inductor and a current source, the first circuit being configured to convert an input voltage into an output voltage based on a switching operation of the first switch and the second switch; and   processing circuitry configured to,
 generate a first reference voltage and a second reference voltage, 
 control the switching operation of the first switch and the second switch based on an inductor current flowing in the inductor, the output voltage and the first reference voltage, 
 reduce the first reference voltage and the second reference voltage to a reset voltage during a soft-stop time period of a soft-stop phase, and 
 control a discharge current flowing in the current source in the soft-stop phase based on a magnitude of the inductor current, the output voltage and the second reference voltage. 
   
     
     
         2 . The voltage converter of  claim 1 , wherein the first circuit further includes:
 a bulk capacitor configured to store a bulk voltage, the bulk voltage being corresponding to the input voltage from which a noise is removed, and the bulk capacitor being connected between a first node and a ground node; and   an output capacitor configured to store the output voltage, the output capacitor being connected between an output node and the ground node,   wherein
 the first switch is connected between the first node and a second node, 
 the second switch is connected between the second node and the ground node, 
 the inductor is connected between the second node and the output node, and 
 the current source is connected between the output node and the ground node. 
   
     
     
         3 . The voltage converter of  claim 2 , wherein
 the processing circuitry is configured to cause the first switch and the second switch to perform the switching operation such that the output voltage is equal to or greater than the first reference voltage; and   the first circuit is configured to perform the switching operation such that the inductor current does not flow from the second node to the first node in the soft-stop phase.   
     
     
         4 . The voltage converter of  claim 3 , wherein
 the processing circuitry is configured to cause the switching operation to be performed in response to detecting that the output voltage is equal to the first reference voltage; and   the switching operation includes,
 turning on the first switch for an on time period, the second switch being turned off for the on time period, 
 turning off the first switch based on termination of the on time period, and 
 turning on the second switch based on termination of the on time period. 
   
     
     
         5 . The voltage converter of  claim 4 , wherein
 the output voltage is reduced to the reset voltage during the soft-stop time period; and   the output voltage becomes equal to the reset voltage corresponding to termination of the soft-stop phase.   
     
     
         6 . The voltage converter of  claim 5 , wherein the processing circuitry is configured to:
 cause the first switch and the second switch to perform the switching operation in the soft-stop phase based on the magnitude of the inductor current not being zero; and   perform first operations based on the magnitude of the inductor current being zero, the first operations including,
 causing the first switch and the second switch to turn off, and 
 cause the current source to generate the discharge current, the output voltage being discharged to the reset voltage based on the discharge current. 
   
     
     
         7 . The voltage converter of  claim 6 , wherein
 the current source is a discharge transistor controlled by a discharge voltage; and   the discharge transistor is configured to cause the discharge current to flow according to the discharge voltage.   
     
     
         8 . The voltage converter of  claim 1 , wherein the processing circuitry is configured to generate the second reference voltage by adding an offset voltage to the first reference voltage. 
     
     
         9 . The voltage converter of  claim 8 , wherein the processing circuitry is configured to reduce the offset voltage to zero during the soft-stop time period. 
     
     
         10 . The voltage converter of  claim 1 , further comprising:
 an active discharge circuit,   wherein
 the processing circuitry is configured to,
 detect the magnitude of the inductor current, and 
 generate a zero-current signal based on the magnitude of the detected inductor current and 
 
 the active discharge circuit is configured to generate a discharge voltage based on the output voltage, the second reference voltage and the zero-current signal, the current source being controlled based on the discharge voltage. 
   
     
     
         11 . The voltage converter of  claim 10 , wherein the processing circuitry is configured to:
 generate the zero-current signal at a logical low level in the soft-stop phase based on the magnitude of the inductor current not being zero; and   generate the zero-current signal at a logical high level in the soft-stop phase based on the magnitude of the inductor current being zero.   
     
     
         12 . The voltage converter of  claim 11 , wherein
 the active discharge circuit is implemented based on an amplifier including a non-inverting terminal, an inverting terminal, an enable terminal and an output terminal;   the enable terminal is configured to enable the amplifier in response to the zero-current signal at the logical high level; and   the amplifier is configured to output the discharge voltage to the output terminal based on the output voltage received to the non-inverting terminal and the second reference voltage received to the inverting terminal.   
     
     
         13 . The voltage converter of  claim 1 , wherein the processing circuitry is configured to:
 generate a ripple injected voltage by injecting a ripple voltage into the output voltage;   generate a driver control signal based on the ripple injected voltage, the inductor current and the first reference voltage; and   generate a first drive signal and a second drive signal based on the driver control signal, the first switch being controlled based on the first drive signal, and the second switch being controlled based on the second drive signal.   
     
     
         14 . The voltage converter of  claim 13 , wherein the processing circuitry is configured to:
 control the switching operation of the first switch and the second switch based on the first drive signal and the second drive signal in the soft-stop phase based on the magnitude of the inductor current not being zero; and   turn off both of the first switch and the second switch based on the first drive signal and the second drive signal in the soft-stop phase based on the magnitude of the inductor current being zero.   
     
     
         15 . A soft-stop operation method of a voltage converter, comprising:
 reducing, by processing circuitry, a first reference voltage and a second reference voltage to a reset voltage during a soft-stop time period, an offset voltage being added to the first reference voltage to obtain the second reference voltage;   detecting, by the processing circuitry, a magnitude of an inductor current flowing in an inductor included in a first circuit, an output voltage of the first circuit being equal to or greater than the first reference voltage;   stopping, by the processing circuitry, a switching operation in response to the magnitude of the inductor current being zero, the stopping being performed by controlling a first switch and a second switch included in the first circuit;   causing, by the processing circuitry, a discharge voltage to be provided to a current source in response to the magnitude of the inductor current being zero, the current source being included in the first circuit;   generating, by the current source, a discharge current in response to the discharge voltage; and   discharging, by the current source, the output voltage to the reset voltage based on the discharge current.   
     
     
         16 . The soft-stop operation method of the voltage converter of  claim 15 , wherein the causing the discharge voltage to be provided to the current source includes:
 generating, by the processing circuitry, a zero-current signal at a logical high level in response to the magnitude of the inductor current being zero; and   generating, by an active discharge circuit, the discharge voltage based on the output voltage and the second reference voltage in response to the zero-current signal at the logical high level.   
     
     
         17 . The soft-stop operation method of the voltage converter of  claim 15 , wherein the stopping the switching operation includes:
 generating, by the processing circuitry, a driver control signal for the first switch and the second switch to stop the switching operation in response to the magnitude of the inductor current being zero; and   causing, by the processing circuitry, both of the first switch and the second switch to turn off based on a first drive signal and a second drive signal in response to the driver control signal.   
     
     
         18 . A voltage converter comprising:
 a first circuit including a current source for discharging an output voltage; and   processing circuitry configured to,
 cause a discharge voltage to be generated based on an inductor current flowing in an inductor, the inductor being included in the first circuit, and 
 perform a soft-stop operation including causing the discharge voltage to be provided to the current source based on a magnitude of the inductor current being zero, the current source being configured to generate a discharge current in response to the discharge voltage, and the discharge current causing the output voltage to discharge to a reset voltage. 
   
     
     
         19 . The voltage converter of  claim 18 , wherein
 the first circuit includes a first switch and a second switch that convert an input voltage into the output voltage by a switching operation; and   the processing circuitry is configured to perform the soft-stop operation including causing the first switch and the second switch to stop the switching operation.   
     
     
         20 . The voltage converter of  claim 18 , wherein the processing circuitry is configured to:
 generate a first reference voltage and a second reference voltage, the output voltage being equal to or greater than the first reference voltage; and   perform the soft-stop operation including causing the discharge voltage to be generated based on the output voltage and the second reference voltage in response to the magnitude of the inductor current being zero.